he was making a case today but before a world audience of allies and adversaries at the united nation. he gave a passionate tribute to the u.s. ambassador killed in libya and called on the world to make a stand against extreme is. here's jake tapper. >> reporter: the president made the focus of his united nations speech about a man who wasn't there. >> i would like to begin today by telling you about an american named chris stevens. >> reporter: with a tribute to a u.s. ambassador to libya, attacked and killed in the dead of night in beghazi two weeks ago today. today -- extolling the humanity and hope stevens stood for. >> if we are serious about those ideals, we must speak honestly about the deeper causes of the crisis. today, we must affirm that our future will be determined by people like chris stevens, and not by his killers. >> reporter: but, in many ways, the president's address seemed targeted at his domestic audience -- accused by republicans of glibly down playing the unrest in the muslim world, the president demanded an end to the violence. >> there is no speech that justif